Physics _ Please please help
posted by Alexandria on .
A hollow brass cylinder is weighed on a pan balance (kitchen scale) which read in kg. The scale reading is 5.56 kg. The brass cylinder is now removed from the scale and is replaced by a beaker of liquid density 1.56 * 10^3 kg/m^3; the scale now reads 17.50 kg. The brass cylinder is then suspended from a thread, and it is lowered into the liquid until it is completely immersed but does not touch the bottom of the beaker. The reading of the balance increases from 17.50 kg to 28.28 kg when the cylinder is immersed in the liquid. The density of brass is 8.47 * 10^3 kg/m^3.
(I) Calculate the volume of metal in the cylinder.
(II) Calculate the upthrust (buoyancy force) exerted on the hollow cylinder when it is totally immersed in the liquid.
(III) Calculate the volume of the hollow space inside the cylinder.

something is confusing me. How can the mass of the liquid+brass combined be greater than each separately?

Not sure but that's how the question goes.

alexandria, something is wrong with the construction of the problem. The weight of two people on a scale cannot be greater than the sum of both their weights.

It's ok thank you anyway

I think it would be; density difference: 8.47 * 10^3 kg/m^3  1.56 * 10^3 kg/m^3 = 6.91kg/m^3
Change in weight we have 28.2817.50= 10.78kg
mass/density=volume
10.78/6.91=1.56